Retrievable gun perforator



Aug. 22, 1944. E. F. RAYMOND RETRIEVABLE GUN PERFORATOR Filed June 2l, 1945 IN VEN TOR.

rroP/vfy Patented Aug. 22, 1944 UNiTeD stares rem orricr.

14 Claims.

This invention has to do with improvements in gun perforators for use in wells, and particularly of the type disclosed in my copending application Serial No. 440.319, filed April 24, 1942, for Gun perforation in wells, and Serial No. 491,596, filed on even date herewith, on Gun perforator.

The general type of gun perforator with which the present invention, as well as the above mentioned copending applications are concerned, is one diiering characteristically from conventional gun perforators in that it is of a drop-in type, comprising one or more gun units carried by or contained in a body adapted to be dropped or lowered along a cable run in the well in advance of the perforator proper. In accordance with its preferred form, the perforator is run into the well along a cable extending through an opening or passage in the perforator body, and the gun unit or units are fired by actuation of a firing mechanism resulting from its engagement or association with an abutment positioned at a predetermined depth in the well. The abutment may be carried directly on the cable itself, and may have such co-action with the gun firing mechanism that upon reaching the predetermined depth at which the abutment is positioned, the gun unit or units will be red automatically, and simultaneously or sequentially, all as will later appear. Under normal circumstances, Where the well bore or casing is Suniciently straight and large to permit free movement or falling of the perforator body to the ring depth, the perforating operation is accomplished simply by dropping the body along the cable to the depth of the abutment, thereby automatically firing the gun units, and retrieving the perforator by pulling it out of the Well on the cable and in engagement with the abutment.

The present invention is concerned with what may be regarded as a safety feature, to permit recovery of the perforator if for any reason it fails to reach the firing depth, and to do so by means assuring against ring of the gun units. Thus where the condition of the hole, as in the event of obstructed or collapsed casing, causes the perforator to lodge at some location above a predetermined firing depth, the invention provides for the recovery of the perforator without danger of inadvertent ring, all to the end that the well obstruction may be removed to permit normal running of the perforator.

One of my major objects is to permit interconnection between the perforator body and the cable at any location along the cable above the point of engagement between the perforator and the cable-carried abutment. In this manner, recovery of the perforator is made entirely independent of its engagement by the abutment, and hence inadvertent firing cannot occur. Although in the broad aspects of the invention it is contemplated that various types and forms of connections may be used to so interengage the perforator and cable, I preferably use a gripping-type connection brought into holding engagement with the cable by a go-devil or actuating member dropped into the well from the ground surface. Thus, as will appear, I may use one or more radially movable cable gripping elements carried by the perforator body, and caused to inter-connect the body and cable by a tubular go-devil, which when dropped into the well on the cable, is brought into wedging and radially contracting engagement with thegripping element or elements.

The general features and objects of the invention. as Well as additional aspects and the details of a typical and preferred embodiment, will be more fully understood from the description to follow, throughout which reference is had to the accompanying drawing in which:

Fig. 1 is a longitudinal section View of the gun perforator in the well casing, the cable gripping assembly at the top of the perforator body appearing in elevation;

Fig. 2 is a fragmentary View showing the upper end portion of the perforator in elevation, and the cable gripping assembly, as well as the lower end of the go-devil, in section;

Fig. 3 is a view similar to Fig. 2 showing the gripping elements brought into holding engagement with the cable;

Fig. l is an enlarged cross section on line 4-4 of Fig. 2; and

Fig. 5 is a cross section on line 5-5 of Fig. 2.

Referring first to the general View of Fig. 1, the perforator, generally indicated at l0 and received with clearance at il within the well casing l2, is shown to comprise an elongated body B .containing one or more gun units Iii. The perforator is adapted to be dropped into the casing about a cable l5, such as the usual sand line, contained Within and extending through the perforator body.` For the purposes of the present application, it will suiiice to describe only` generally the assembly including the gun units, cable passage, the ring mechanism and such parts, since the invention is independent of their particular details. For a complete explanation and illustration of the perforator parts other than the present safety feature, reference may be had to my copending application Serial No. 491,596, on Gun perforator.

Section I3 of the body is contained within a split sleeve I6 slotted along one side at I1 and I8, see Fig. 2, to shoulder at I9 on section I3 and permit access, within the area of slot I1, to nuts which hold a second body section 2| in position. This latter section is coextensive with section I3, and relative longitudinal movement of the sections is prevented by, their nter-engagement at shoulders 22,23 and 24. Section 2| threaded the nuts 20 to interlock the parts.

The cable I5 passes axially into the upper end portion of the body through an opening 26 be` tween the sections, the cable being deflected by guides or rollers 21 carried within section 2|, to

pass downwardly in offset relation to the intermediate length of the body. The cable thence is returned between rollers 28 into axial alinement within the lower end of the body, from which the cable passes below as indicated. The cable carries on its lower end a suitable abutment 29 which, as will be understood, is' positioned at a selected depth in the well, determined by the section of the casing to be perforated by the gun mechanism.

. As fully explained in my copending application referred to above, each of the gun units I4 contains a projectile which iscaused to be fired as a result of upward displacement of an elongated firing member 30 upon engagement of its lower end portion Ilia, which projects below the bottom of the body, with the abutment 29. The ring member 30 is contained Within slots 3I and 32 in ther body section 2 I, is is displaceable in its firing travel :between the limits of engagement with shoulders 33 and 34, to discharge the gun units simultaneously or sequentially.

. If desired, free falling of the perforator at an excessive rate may be suitably restrained, as by a guide sleeve 35 conned between the upper end of sleeve I6 and sleeve nut 36, the lower end of the guide sleeve also engaging the shoulder 31, see Fig. 2, on body Section I3 at the upper end of the sleeve slot I8. Sleeve 35 is of open formation, having bowed portions 38 engageable with the casing I2 to frictionally restrain free falling of the perforator.

Under normal conditions of operatio-n, and with the casing free of obstruction, the perforator first is assembled about the cable at the ground surface by applying body sections I3 and 2 I, with their contained parts, to the cable, then placing sleeves I6 and 35 about the body sections, and finally securing sleeve 35 in place by threading nut 36 on the upper end ofthe body. The perforator then is dropped down along the cable, assuming of course the abutment 29 t'o have been properly positioned. Upon striking the abutment, the firing member 30 causes the gun units I4 to fire through the section of the casing directly above the abutment. Resting on the abutment, Vthe perforator then is pulled out of the well on the cable. Y

The safety feature with which the invention is concerned, comes into use when for any reason lowering of the perforator is arrested above its proper firing position, as when an obstruction such as a collapsed section Ila of the casing is encountered. Under such circumstances. my purpose is to permit removal of the perforator on the cable independently of any supporter encarries integral bolts on which are gagement by the abutment 29 that would cause the gun units to fire.

The safety device, generally indicated at 40, comprises a cage 4 I which may be associated with or connected to the upper end of the perforator body in any suitable manner. Typically, the cage 4I is shown to have abottom flange 42 bearing and clamped against the top end of the perforator body by sleeve nut 36, the latter having, as shown in Fig.r2, mutilated or substantially 90 threads 43y to permit ready making and breaking of the connection. The cage 4I has a central or body section 44 containing an opening 45 through which the cable I5 passes, it being contemplated that section 44 may be made as a single piece,

or of slotted (e. g. slotted at S) or sectional character to facilitate its application about the cable.

Section 44 is transversely slotted at 46 to receive a pair of gripping elements 41 which normally rest upon the upper end of the perforator body, see Fig. 2, when in radially expanded condition. tained within the cage structure by a pair of closure sections 48 having slots 49 and 50 through which the Wing portions 41a of the gripping elements project. Sectionsn 48 may be detachably secured by section 44 to permit insertion and removal of the gripping elements, by any suitable means such as screws I5D. As shown inFig. 2, the wing portions 41a of the gripping elements project radially through slots 50, and present angular or inclined wedge faces 5I for engagement by the angular bore of the go-devil. Normally the gripping element may be maintained in expanded positions by suitable spring elements 60 seating within shallow grooves 6I in -the elements.

The go-devil 52 preferably has a tubular body of suilicient length to give the desired mass or Weight, made in sections 53 and 54, see Fig. 5, interconnected rby screws 55 for application to the cable, and containing a central opening 56 through which the cable extends. The bottom end of the body contains a tapered or frustroconical bore 51 from which fluid passages lead as at 58.

When dropped into the well about the cable, the lo-Wer end of the go-devil telescopes over the cage 4I, bringing the bore 51 into wedging engagement with surfaces 5I of the cable gripping elements. As a result, the gripping elements are released from springs 60 and are forced radially inward to tightly engage the cable, the gripping element teeth 59 desirably having a downward pitch, as illustrated, in order that they may tend to bite into the cable as the latter is raised to assume the load. It will be understood that in their cable gripping positions, the elements 41 may be somewhat elevated from engagement attached to the cable, the perforator may be removed from the well independently of the cable or abutment. below.

I claim:

1. A retrievable gunperforator for use in wells.

for interconnecting the'body and cable at dif- Y ferent locations along the cable to permit re- The gripping elements 41 are re.

moval of the perforator on the cable from different depths at which the perforator may become lodged in the well.

2'. A retrievable gun perforator for use in Wells, comprising a body movable downwardly along a cable lowered in the well in advance of the perforator, a gun unit within the body, and means carried by the body and engageable with the cable at different locations therealong to permit removal of the perforator on the cable from different depths at which the perforator may become lodged in the well.

3. A retrievable gun perforator for use in wells, comprising a body movable downwardly along a cable lowered in the well in advance of the perforator, a gun unit within the body, and means operated by a go-devil dro-pped into the well for interconnecting the body and cable at diierent locations along the cable to permit removal of the perforator on the cable from different depths at which the perforator may become lodged in the well.

4. A retrievable gun perforator for use in wells, comprising a body movable downwardly along a cable lowered in the well in advance of the perforator, a gun unit within the body, means for firing the gun unit when the body reaches a predetermined iiring depth in the well, and means for interconnecting the body and cable at different locations along the cable to permit removal of the perforator on the cable from different depths above said ring depth and at which the perforator may become lodged in the Well.

5. A retrievable gun perforator for use in wells, comprising a body movable downwardly along a cable lowered in the well in advance of the perforator, a gun unit within the body, means for firing the gun unit when the body reaches a predetermined ring depth in the well, and means operable by a go-devil dropped into the well to connect the body with said cable at any location therealong to permit removal of the perforator on the cable from any depth above said ring depth at which the perforator may become lodged in the well.

6. A retrievable gun perforator for use in wells, comprising a body movable downwardly along a cable lowered in the well in advance of the perforator, a gun unit within the body, an abutment carried by the cable, ring means engageable with said abutment to re said gun, and means for interconnecting the body and cable at a location above said abutment to permit removal of the perforator on the cable from different depths at which the perforator may become lodged in the well above the point of engagement of said ring means with the abutment.

7. A retrievable gun perforator for use in wells, comprising a body adapted to be dropped into the well along a cable lowered in the well in advance of the perforator, a gun unit within the body, an abutment carried by the cable, iii-ing means engageable with said abutment to fire said gun, and means for interconnecting the body and cable at any location above said abutment to permit removal of the perforator on the cable in the event said body becomes lodged in the well in advance of engagement of said Iiring means with the abutment.

8. A retrievable gun perforator for use in wells, comprising a body movable downwardly along a cable lowered in the well in advance of the perforator, a gun unit within the body, and cable engaging means carried by the body and comprising movable gripping means engageable with the cable at different locations therealong to permit removal of the periorator on the cable from the well.

9. A retrievable gun perforator for use in wells, comprising a body movable downwardly along a cable lowered in the well in advance o the perforator, a gun unit within the body, and cable engaging means carried by the upper end of the body and comprising a movable element adapted to be brought into gripping engagement with the cable by a goedevil dropped about the cable into the well.

10. In combination with a gun periorator comprising a body movable downwardly about and along a cable lowered in the well in advance of the perforator; cable engaging means carried by the upper end of the body and comprising a movable gripping element, and a member adapted to be dropped about the cable into engagement with said element to cause it to grip the cable.

11. In combination with a gun perforator comprising a body movable downwardly about and along a cable lowered in the well in advance of the perforator; cable engaging means carried by the upper end of the body and comprising a movable gripping element, having an upwardly facing wedge surface, and a member adapted to be dropped about the cable and having a wedge surface engageable with said wedge surface of the gripping element to cause said element to grip the cable.

12. In combination with a gun perforator comprising a body movable downwardly about and along a cable lowered in the Well in advance of the perforator; cable engaging means carried by the upper end of the body and comprising a pair of radially movable gripping elements, and a tubular member adapted to be dropped about the cable into engagement with said elements to force them into gripping engagement with the cable.

13. In combination with a gun perforator comprising a body movable downwardly about and along a cable lowered in the well in advance of the perforator; cable engaging means carried by the upper end of the body and comprising a movable gripping element movable radially from an outer position into gripping engagement with the cable, means releasably holding the element in said outer position, and a tubular member adapted to be dropped about the cable to actuate said gripping element.

14. In combination with a gun perforator comprising a body movable downwardly about and along a cable lowered in the well in advance of the perforator; cable engaging means carried by the upper end of the body and comprising a movable gripping element, andan elongated tubular member comprising connected longitudinal sections applied about the cable, adapted to be dropped into engagement with said element to bring it into gripping engagement with the cable.

EDWARD F'. RAYMOND. 

